Shark proof cage
A shark proof cage is an extremely strong metal cage used by a SCUBA diver to safely examine dangerous types of sharks up close, such as the Great White shark or bull shark. Shark proof cages are built to withstand being rammed by large, powerful sharks. The cages provide a visual and tactile deterrent to sharks. Cage diving allows people to come very close to sharks and is mainly used for Great White sharks.
The shark proof cage is also used in the controversial exercise of shark baiting where tourists are lowered in a cage while the tour guides bait the waters for sharks, often leading to aggressive behaviors by the shark population.[1]
On September 4, 1979, US patent number 4166462 was issued for a self-propelled shark proof cage;[2] the cage was designed to allow abalone divers to collect abalone without becoming vulnerable to attack.[2] Thanks to the propulsion system, the abalone divers would exert themselves less and therefore be able to collect their prey for longer periods of time.[2] The patent abstract details a self-propelled cage with at least one access opening and a propeller mounting frame that carries both an air motor and a propeller. Buoyant objects are attached to the frame so that the cage may be made approximately the same density as saltwater.[2]</ref> This patent expired on September 4, 1996.[2]
Shark cage accidents
In 2005 a British tourist, Mark Currie, was nearly killed when a 20-foot great white shark bit through the bars of Currie's shark cage during a recreational shark dive off the coast of South Africa.[3][4] The shark circled several times before charging the cage; it bit through a portion of the cage and then severed it from the cable connecting it to a boat on the surface. Currie realized that his cage was sinking as the shark mounted what would have been its final and fatal attack. Currie quickly swam out of the top of the cage and was pulled to safety by the boat's captain, who fended off the shark with blows to its head.[4]
In 2007, a commercial shark cage was destroyed off the coast of Guadalupe Island after a 15-foot Great White shark became entangled in it and tore the cage apart in a frantic effort to free itself.[5][6][dead link] Tourists captured video of the incident,[6][dead link] which quickly spread throughout the Internet.
Opponents of the cage diving industry, such as marine biologist Craig Bovim, believe that the constant shark-baiting used to lure sharks to tourists' cages creates a "Pavlovian response" in the sharks, causing them to become eager to attack humans for food.[7] Bovim's opponents, such as noted marine environmentalist Wilfred Chivell, contend that there is no correlation between shark-baiting and shark attacks against humans.[7]
References
- ^ "Maui not biting on toxic shark feeder bait". Cyber Diver News Network. July 10, 2009
- ^ a b c d e "Patent 4166462" www.patentstorm.us
- ^ "He Almost Became Shark Food". CBS News. February 11, 2009. Retrieved 10 September 2012.
- ^ a b [1] UnderwaterTimes.com
- ^ http://video.yahoo.com/watch/4102651/11065546
- ^ a b "Great White Shark Accident in Isla de Guadalupe" www.travelistic.com
- ^ a b "Stop Shark Cage Diving Say South Africa Shark Attack Victims". Cyber Diver News Network
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